1. Field
This disclosure relates generally to a bandgap reference circuit, and more specifically, to a bandgap reference circuit with a startup circuit.
2. Related Art
Bandgap reference circuits are commonly used in integrated circuits to provide a temperature independent bandgap voltage. However, bandgap reference circuits may be unpredictable upon power up. Once powered up, bandgap reference circuits operate at a stable operating point to provide the desired bandgap voltage. However, bandgap reference circuits also typically have a second stable operating point when the current is close to zero which provides an undesirable bandgap voltage (i.e. an erroneous bandgap voltage). Therefore, many bandgap reference circuits include a startup circuit which forces current to start flowing during power-up in order to prevent stabilizing at the undesirable bandgap voltage. However, in order to ensure proper operation of the bandgap reference circuit, the startup circuit needs to be disabled appropriately over a wide range of supply voltages.